The standardized method of evaluating the efficacy of a method of treatment has been to conduct controlled, prospective treatments using clinically relevant endpoints as the main outcome measure. However, in the case of several pathologies such as retroviral infections and diseases, and particularly HIV infection and AIDS, the standard endpoints of death or the development of new AIDS defining opportunistic infections or neoplasms often take months or years to reach. Therefore, several medical and government authorities, including the Federal Drug Administration, have now accepted various laboratory markers which serve as surrogate endpoints for quickly evaluating and establishing the utility of new treatments and particularly anti-retroviral treatments.
Surrogate markers suggested for retroviral infections or diseases, and particularly HIV infection and/or AIDS include, but are not limited to, T4 helper cell levels, neopterin levels and .beta..sub.2 -microglobulin levels. See, Hutterer et al. J. Infect. Dis. J. 165:783-784, April, 1992; Ellaurie et al. Ped. Infect. Dis. J. 11: 4,286-289, April, 1992; Jacobson et al., Brit. Med. J. 302:73-78, Jan. 12, 1991; Muller et al., Clinica Chimica Acta 201:1-16 (1991); Keller et al., Cells of the Hepatic Sinusoid 3:414-416 (1991); Polis et al., Am. J. Med 89: 701-704, December, 1990; Harrison et al., J. Med Vir. 32:128-133, 1990; Fuchs et al. Clin. Chem. 35:8, 1746-1749, 1989.
Acquired immunodeficiency syndrome (AIDS) is a fatal condition caused by the human immunodeficiency virus (HIV). At least two strains, and possibly more, of HIV have been isolated and identified. HIV-1 is the virus associated with AIDS in most western countries. HIV-2, which is immunounreactively distinct from HIV-1, is associated with AIDS in western Africa.
Since AIDS was identified as a medical condition in 1981, increasing numbers of cases are being reported worldwide, with a large concentration of these cases in the United States. Researchers believe that most carriers of HIV will eventually develop the symptoms of AIDS. However, the period between initial infection by HIV and/or detection of HIV infection and symptomatic AIDS disease is highly variable, as is the rate of immunological decline. The median time between HIV seroconversion and the development of AIDS presently is believed to be about seven to eleven years. Infections by HIV have proven notoriously difficult to treat, and prophylactic or therapeutic vaccines for these infections are presently unavailable and may never be available.
When challenged by retroviral infection, and particularly HIV infection, individuals appear to display one or more of depressed T4 cell levels, elevated neopterin levels, and elevated .beta..sub.2 -microglobulin levels. Past studies involving the use of beta-carotene in manipulating such endpoints are equivocal at best.
Alexander et al., Immunology Letters 9:221-224, 1985 fed relatively low oral doses of 180 mg/day of beta-carotene for two weeks to normal human volunteers. T4 cells numbers increased up to approximately 30%, but the increase declined to insignificant levels within one week after discontinuing the beta-carotene administration even though a significant elevation in beta-carotene plasma level was still seen six weeks after treatment was discontinued.
However, Ringer et al., Am. J. Clin. Nutr. 53:688-694, 1991, were unable to identify any effects of beta-carotene ingestion on various immunological indices when beta-carotene was administered in dosages of 0, 15, 45, 180 and 300 mg/day for one month to normal, healthy human subjects. Particularly, Ringer et al. did not find an increase in T4 cells at two or four weeks in humans ingesting dosages of beta-carotene ranging from 15 to 300 mg/day.
Kanofsky et al. Med. Trib., 26-31, Apr. 22, 1987 even cautioned that based upon the results of Alexander et al., any immuno-stimulating action of vitamin A or beta-carotene might actually enhance the replication of HIV in HIV-infected individuals. Kanofsky et al. reported the attenuation of the decline of cell-mediated immunocompetence in animals exposed to variables such as trauma, malnutrition, infection, psychological distress, irradiation, cytotoxic agents, and an array of drugs. Particularly, Kanofsky et al. reported providing vitamin A supplementation of approximately 10 to 15 times the recommended dietary allowance of vitamin A to animals exposed to the retrovirus Moloney murine sarcoma virus.
An increased number of activated macrophages and an increased percentage of cells with markers for Ia.sup.+ cells and macrophages was associated with a retarded death rate during infection with LP-BM5 murine leukemia in C57BL/6 mice which were fed high dietary vitamin A in a study by Watson et al., Life Sci. 43:XIII-XVIII, 1988. Nashima et al., Med. Microbiol. Immunol., 176:189-198, 1987 reported that, in vitro, the vitamin A derivative, retanoic acid, inhibited the replication of HIV.
In a study of eleven HIV-infected individuals, daily administration of 30 mg of beta-carotene for four months was found to increase the number of cells with natural killer cell activity, IL-2R (interleukin-2 receptors), and transferrin receptors. The reported increase appeared to peak after three months of treatment, and some markers appeared to decline by four months. No significant changes in T-helper (T4), T-suppressor (T8), or total T-cells were observed. Watson et al., V. International Conference on AIDS, C632, 663, 1989.
Prabhala et al., Cancer 6:1556-1560, Mar. 15, 1991, demonstrated that different retinoids and carotenoids have different immunomodulatory effects in the inhibition of malignancies. Different subjects having either oral leukoplakia or Barret's esophagus were given 30 mg/day of beta-carotene or 1 mg/kg/day of 13-cis-retanoic acid (13-cRA). The predominant effect of 13-cRA was on the percentage of cells expressing T-helper markers, while beta-carotene was observed to increase natural killer cell markers. Although T-helper marker expression was increased to a small extent in these cancer patients, no significant changes in total lymphocyte, total T-cell, or T-suppressor cell numbers were reported.
Another carotenoid, halocynthiazanthin, which was isolated from a red sponge from the Gulf of Eilat in the Red Sea, was described as unique among the carotenoids as a specific anti-HIV reverse transcriptase inhibitor by Loyu et al., Arch. Biochem. Phys. 293:2,28-212, March, 1992.
Garewal et al., Symposium: Nutrition, Immunomodulation and AIDS, 1992 studied the effect of low dosages of beta-carotene on HIV-infected patients. Each subject received 60 mg of beta-carotene daily for four months. Increases in the percentages of cells expressing Leu II (natural killer cells), Ia antigen, and transferrin receptor (activated lymphocytes) were observed after three months of treatment, but diminished thereafter. Major changes were not seen in total lymphocyte count or in the percentage of cells expressing CD11, CD8, or CD4 antigens.
Ozonoids of terpenes, including ozonoids of beta-carotene, have been disclosed for the treatment of viral infections including HIV-infections by Herman, U.S. Pat. Nos. 4,983,637; 5,086,076; and 5,126,376.
It has now been discovered that the administration of beta-carotene in amounts that can not be achieved dietarily and in amounts previously believed to be significantly high, are effective in the therapeutic control and normalization of various immunological and/or serological indices.